About Charles Rodrigues
Charles Rodrigues was botn in Massachusetts of Portuguese descent. After World War II he studied cartooning at the Cartoonist's and Illustrator's School (now the School of Visual Arts in NYC) under the GI Bill. Rodrigues contributed cartoons to HiFi Review (later Stereo Review) starting in 1958. He also contributed to many magazines including The Realist and National Lampoon. rodrigues died in 2004.
I doubt that the Fletcher-Munson experiment based on single isolated sine waves represent the way our brain processes natural sounds being composed of a base tone and multiple overtones in a background noise field. Better they should have played different instruments and asked the listeners when they would perceived same loudness level. Sound pressure level meters might have given then most astonishing results giving correlations based on natural psychoacoustic.